Adam Samuel Bennion was born on December 2, 1886, in Taylorsville, Utah, to parents Joseph Bushell Bennion and Mary Ann Sharp. Bennion married Minerva Richards Young on September 14, 1911, and together they had five children. Bennion graduated from the University of Utah in 1908. From 1911 to 1913, Bennion attended Columbia University, where he earned his masters degree. He completed his doctorate at the University of California (Berkeley) from 1921 to 1923. For most of his career he worked in education: He taught at the LDS High School in Salt Lake City and was made Superintendent of Church Schools in 1919. He also helped expand the Church's seminary program during the early twentieth century.

He also wrote and published four books: "The Candle of the Lord" (1958), "Looking in on Greatness: Written for LDS Junior Seminaries" (1935), "Principles of Teaching" (1921), and "What it Means to be a Mormon" (1917). In 1927, he worked for Utah Power and Light Company and in 1944 he ran as a Republican candidate for the United States Senate. After his unsuccessful run, he became the director of the Denver and Rio Grande Railroad. On April 9, 1953, he was called by Prophet David O. McKay to be a member of the Quorum of the Twelve Apostles.

Bennion died on February 11, 1958, in Salt Lake City, Utah.